Agent Pickering was there to do an interview with everyone and she gets to Temperance and mentions a Juan Guzman.
Agent Pickering: When you were in Cuba, did you meet with a man named Juan Guzman?

Dr. Temperance 'Bones' Brennan: [pause. Bones picks up her phone and dials a number] Hello. It's Dr. Brennan from the Jeffersonian. You told me to call you if anyone asked about... you know... him... Someone from the State Department named Samantha Pickering.

One of the big flaws of the show is how little follow-up there is on story threads. The show is very consistent as far as episode structure and characterization (for the most part), but it can be utterly disjointed when viewed as a series of episodes.

This gets arguably worse / more apparent in the later seasons, as characters have bigger life events occur as plot points that are then either never spoken of again, or only casually mentioned a few episodes later.